As wild and promising as that month of Tennessee Titans football was, all the momentum, goodwill and “respect us” talk can be flushed with one bad afternoon in Buffalo.

Then again, as reliable as this Titans defense has been amid chaotic circumstances, it can be better. That’s where Sunday in Buffalo — and an attempt to reach 4-1 for the franchise’s best five-game start since it was 5-0 in 2008 — hinges. That’s why wins over Houston, Jacksonville and Philadelphia were possible, even for all the focus on an injury-challenged offense that finally broke out against the Eagles.

And just imagine if first-round pick Rashaan Evans comes on as an inside linebacker the way second-round pick Harold Landry has already as a pass rusher. It’s really not much of a leap, based on the bursts we’ve seen on the field from Evans and the fact that he didn’t have a training camp.

Titans defensive tackle Jurrell Casey (99) celebrates after a play in the second quarter against the Eagles at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Titans linebacker Wesley Woodyard (59) calls for the fans to get loud during the first quarter against the Eagles at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Wesley Woodyard, injured Sept. 30: Inside linebacker Wesley Woodyard suffered a shoulder injury in the first quarter of the Titans’ win against the Philadelphia Eagles on Sept. 30. He missed game 5 in Buffalo. Here, Titans head coach Vrabel and medical personnel tend to the injured Woodyard (59) in the first quarter of the Eagles game at Nissan Stadium. Andrew Nelles / Tennessean.com

Titans quarterback Marcus Mariota (8) scrambles out of the pocket on the first possession of the game against the Eagles at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Titans place kicker Ryan Succop (4) gets the Titans on the scoreboard with a field goal in the first quarter at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Titans injured tight end Delanie Walker waves to the crowd as the team's 12th man before the game against the Eagles at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Titans linebacker Derrick Morgan (91) and defensive tackle DaQuan Jones (90) head out to the field before the game at Nissan Stadium Sunday, Sept. 30, 2018, in Nashville, Tenn. George Walker IV / Tennessean.com

Kenny Vaccaro, injured Sept. 30: Safety Kenny Vaccaro suffered an elbow injury while defending a run in the second quarter of the Titans’ win against the Philadelphia Eagles on Sept. 30. He will “miss a few weeks,” Titans coach Mike Vrabel said.Here, Vaccaro (24) makes a catch during warmups before the game against the Eagles at Nissan Stadium. George Walker IV / Tennessean.com

Kylie Mulholland, 11, rides the zipline before the game between the Tennessee Titans and the Philadelphia Eagles at Nissan Stadium in Nashville, Tenn., Sunday, Sept. 30, 2018. Andrew Nelles / Tennessean.com

Cole Sporkin, 6, throws a football before the game between the Tennessee Titans and the Philadelphia Eagles at Nissan Stadium in Nashville, Tenn., Sunday, Sept. 30, 2018. Andrew Nelles / Tennessean.com

Peyton Knight, 9, has his face painted before the game between the Tennessee Titans and the Philadelphia Eagles at Nissan Stadium in Nashville, Tenn., Sunday, Sept. 30, 2018. Andrew Nelles / Tennessean.com

“It’s been a challenge,” said Evans, who injured a hamstring on the first day of pads and wasn’t activated until the second game against Houston. “You can know everything and be able to explain it and stuff like that in the room, but when you get on the field it’s a totally different thing. So me being out there, practicing and executing things in practice, that makes it a lot easier for coaches to want you on the field. For me, my standards are as high as they can possibly be. I’ve been doing my job. But I want to be an elite player, a guy that changes the game. I’m going to keep striving for that and won’t stop until I get it.”

If the Titans are going to beat the 1-3 Bills as they should and set up a Nashville showdown of AFC surprises against Baltimore, this defense has to keep rookie quarterback Josh Allen from getting loose. His talent is obvious. So is his rookie-ness at times.

The Titans are sixth in the NFL in the most important defensive statistic, points allowed, at 18.3 per game — which includes a kickoff return for a touchdown allowed at Miami. They have yet to allow a point in the first quarter.

Jurrell Casey, MVP candidate?

They are No. 1 in the NFL in red-zone defense (20 percent) and No. 7 in third-down defense (34 percent). They are led by defensive lineman Jurrell Casey, listed by NFL.com this week 10th in its league MVP rankings. They are appropriately unimpressed with it all.

“We’re somewhat consistent. But I think we can be better,” cornerback Logan Ryan said. “We’ve flashed some dominance, especially in the Jacksonville game (a 9-6 win), and then last week we weren’t as dominant. We want to be better than good. Good and consistent are OK, but we want to be dominant.”

Defensive coordinator Dean Pees, lured out of brief retirement to join first-year coach Mike Vrabel — whom he coached in New England — has a catalog of creative blitzes that have affected opposing quarterbacks at key moments in the first month.

Pees also has concern about the Titans’ rush defense, which ranks 27th in the NFL in yards allowed per carry (4.9) and 25th in yards allowed per game (118). It was gashed early in a season-opening loss to Miami to change the momentum of that game, long before it became the longest in NFL history thanks to lightning delays. It was punctured in overtime by the Eagles, before the Titans stood up in those two crucial scenarios at once — third down, red zone — to force a field goal and allow Marcus Mariota to win it going the other way.

CLOSE

The Titans took down the defending SuperBowl champs, the Eagles with Corey Davis stepping up in a big way.
Nashville Tennessean

Linebacker Will Compton was on the field and was all over a Carson Wentz attempt to tight end Zach Ertz, breaking it up and nearly picking it.

“That was a guy that understood his job, understood really where the quarterback was going to go in a gotta-have-it situation, and he made a great play,” Vrabel said of Compton. “That’s the definition of a pro.”

Malcolm Butler, promising progress

Compton has been a handy free-agent pickup. A much bigger signing, cornerback Malcolm Butler, has provided good coverage for a lot of the first month but also has been torched too often. This he admits and vows to correct.

But there’s still a lot to like about what this defense has done and what it can be. It’s the foundation of the Titans’ prospects for contending in the AFC.

And it has a young linebacker from Alabama whose athleticism and approach give him a chance to be a contributor of more than random bursts in the next month. With veteran and mentor Wesley Woodyard nursing a shoulder injury he suffered early against Philadelphia, the Titans could use a fast forward from Evans in Buffalo to help them avoid a rewind.

“I see the fire in his eyes to want to go out there and compete, and that’s something that’s equivalent to me and him,” Woodyard said of Evans. “He doesn’t like to be wrong, and he wants to get better every day. If he does something good one day, the next day he wants to do it great. I'm enjoying watching him, man. Long way to go, first game was a little rough, but he’s on the path.”

Contact Joe Rexrode at jrexrode@tennessean.com and follow him on Twitter @joerexrode.